I have a '12 3950 HD and I found some "stress cracks" in it. When talking to the guy in the body shop, he told me that the grey is a gel-coat just like a boat. When they replace my cap, they will shoot it and then clear on top of the gel coat. I asked about the ones turning white and was told that the ones that they had to repaint didn't have any clear on them. He also said that add at least 4 layers of clear and that seemed to keeping them from fading.